Joint for electrical fixtures



NOV. 16, A. c PERBAL JOINT FOR ELECTRICAL FIXTURES Filed Feb. 26, 1942INVENTORI ALBERT C. PERBAL M 3%,

IIIIII Patented Nov. 16, 1943 I UNITED STATES PATENT OFFICE JOINT FORELECTRICAL FIXTURES Albert 0. Perbal, University City, M0. ApplicationFebruary 26, 1942, Serial No. 432,415

2 Claims. (01. 174 ss) My invention relates to improvements in bracketsfor electrical fixtures and the like, and has particular reference to animproved joint for connecting members of an adjustable bracket arm. 7

An object of my invention is to provide a joint of generally elbowcharacter, for connecting adjacent members of a bracket arm or likestructure, wherein the joint afiords substantially universaladjustability of one connected member relative to the other, and is soconstructed as to offer frictional resistance to the relativeadjustments of the bracket members, of a degree which will assuremaintenance of any, such adjustment.

Another object of my invention resides in the provision of a joint ofthis character which is especially suitable for use in articulated armsof an electrical fixture bracket, and which for this purpose, is soconstructed as to provide adequate space within the joint for therelatively free extension of electrical conductors therethrough,

and to aiiord protection for the conductor by preventing rubbing actionthereon by the joint body.

A further object of my invention is to provide an improved and compactjoint comprised of relatively few parts which may be economicallymanufactured and quickly assembled, and wherein the parts are heldtogether in assembly by resilient connector elements or spring clipswhich may be easily manually applied or removed.

Other objects and advantages of my invention will appear readily fromthe following description of a preferred embodiment, thereof, asexemplitied in the accompanying drawing.

In the drawing, Fig. 1 is a side elevational vie of my improved elbowjoint, shown as applied to adjacent ends of members of an electricalfixture arm or bracket; Fig. 2 isa view in longitudinal section throughthe joint, as taken along the line 2--2 of Fig. 1; Figs. 3, 4 and 5 aretransverse sectional views of the joint as taken respectively, along thelines 33, 4-4 and 5-5 in Fig. 2, each showing features of my improvedconstruction; Fig. 6 is a view in perspective, of one of a pair ofcomplemental joint elements constituting the body of my improved joint;Fig. '7 is a perspective view of a ring member employed in my device;Fig. 8 is a view in perspective, of an arm member of the joint, and Fig.9 illustrates in perspective, a spring clip element provided forsecuring the several parts of the joint in assembly.

According to the present exemplary disclosure, my improved device isshown as applied byway of illustration only, to the connection ofmembers 5 and 6 of an adjustable electrical fixture bracket providingthe support for an electrical device such as thelamp socket I. Thebracket members 5 and 6, the former being here shown only in partincluding its joint connected end 8, may be of hollow or tubular form toprovide for the extensionof electrical conductors therethrough, as theconductor cable 9 appearing in Fig. 2.

With reference now to the construction of my improved joint, thepresently preferred form thereof as illustrated, presents a body sectionIt] comprised of a pair of complemental or companion body elements H andI! (Fig. 2), these elements in assembly affording pivotal support for afurther member I4 of the joint. The companion elements II and II are bypreference, unitary or one-piece shell-like members formed from suitablerigid material, and each having the general formation as shown by theperspective view of Fig. 6. Extending longitudinally of correspondingends l5 of these elements, are curved bearing surfaces 16 provided forengagement with the end 8 of the bracket arm 5, and serving in theassembly of the body elements, to journal the body section ID .on the.bracket arm. In order to prevent displacement of the assembled bodysection longitudinally of the bracket arm, recesses I! are formedpreferably in the midsections of, the bearing surfaces l6, and thesecooperate in the assembled body section, to form an annular channel l8as indicated in Figs. 2 and 3. Received in this channel is an outstruckelement or projection 20 (Fig. 2) on the end portion 8 of bracket arm 5,the projection 20 thereby being effective to constrain the body Itagainst movement longitudinally of the bracket arm,

while permitting by reason of the annular extent of the channel I8,rotational movement of the body on the arm. Although the channel l8 maybe completely annular so as to allow unlimited turning of the bodysection of the joint relative tothe arm end 8, where electricalconductors, are extended through the joint as in the present example, itis desirable to restrict such turning in order to prevent inordinatetwisting of the conductors which otherwise would very likely re- .sultin injury thereto. 'To this end then, the annular extent of the channelI8 may-be rendered incomplete as by the provision of a suitable abutmentin one or the other of the channelrecesses H, such as the bar or stopelement 2| shown in Figs. 3 and 6. Thus it will appear that the stopelement 2| will abut the projectionZO 1n the course of turning the bodysection H) on In th formation of the companion shell-like members orbody halves II and I2, the marginal wall portions 22 of each whichextend longitudinally of the member from the end portion I containingthe bearing surface I6, are terminated intermediate the ends of themember as at 23, the terminal ends of these walls being oppositelybevelled as shown in Fig. 6. The end portion 24 of the member beyond thewall terminals 23, is

thereby reduced as clearly appears in Fig, (Land this end portion isformed "to provide a 'flat=bearing seat 25 of arcuate trend. Accordingto the presently preferred embodiirfent, the seat 25 is substantiallythree-quarter circular, or approximately 270 degrees in circular extent.'Upstand ing on the inner periphery of this bearing seat is a flange orshoulder '26 of substantially "corresponding circular extent, the flangeconstituting a pivot bearing forthe pivotal support of the member I4 ofthe joint. It will appear'f-rom the foregoing, that the reduced endportions of the companion elements H and I2 cooperate in assembly, toprovide an aperture 21 therebet'ween (Figs. 2 and 5) to receive apart ofthe member -v I4 presently to be described, and further-{that thebearing seats 25 and flanges 26 are in opposed coaxial relation toprovide the pivotalsupport for such portion of mem'be'r l4, 'asthus willpresently appear. I

The member I! of mydmproved joint is essentially a unitarystructurecomprising an annulus 28 from the periphery of which ex-tendsasubstantially cylindrical "element or head 29, these parts beingjoinedby afi'ie ck'3 il. Theheadffl is hollowed. or recessed axiallythereojf, as at'3l, to receive and mounttheFtiibuIar bracket member 6 (Fig.2), the naer -havmgswurea tolt'the lamp socket I, as indicated the'threaded connection 32. Further, the n'eel r 30 "is longitudinallyapertured as at 33,to-provide"a passage communieating with the openinterior 'of the annulus 213 and the recess 31-, this provision 'beingmade for the through extension o! the conductor cable "9, as illustratedm me-2. 1

In the assembly of-th'e =-coinpahion body elements II and I2andthemember t4 th ea nnulus 2B of the latter isreceived-in thewabperture 21between the reducede'n'd portions 24 of the-body halves, beingjournalle'd therebetween fonpivotal movement about the fia'ng'e's 26-asappears-inFig. 2. While the bearin'g seats 25-'may bear'directly againstthe opposite lateral races 34 of the annulus, with the flanges "26 indirect contact with the opposite lateral "portions "35 "at the innerperiphery of the annulusit is preferred to interpose ring "elements toprovide the actual journalling contactbetween the body section and theannulus. Accordingly, a pairofthese elements,

one of which is illustrated in perspective by Fig. '7, 1

are provided in the present assembly. The-elements 36 may be 'for'med'ofsteel or other suitable material, and each is of fiangedfring shapeconforming to the --surmce-25 and flange 260i the bodymembers-asclearly-shown inthe sectional view of Fig. 5. The ring flangemay be inwardly deformed in spaced zones, as at 31 (Fig. '7) forabutment with the terminal ends 38 of the flange 26, whereby to precluderotational movement of the rings about the flange 26. As appears in Fig.2 the conductor 9 passes through the annulus or eye portion 28 of memberI4 and thence longitudinally through the shell body ID. The rings 36sheath the edges of the said eye portion and prevent direct contacttherewith of the conductor 9, and since the rings are held fixed withrespect to the shell body, the conductors or their insulating coveringsare not rubbed against by the said eye portion when that part isrotated, with reduced wear on the'conductors as a result.

In the assembly of the joint parts, the member I4 through its pivotalsupport as now described, may be plvotally displaced relative to thejoint body as exemplified by the relation of these joint parts inFig. 1. The extent of such movement is here limited by'abutrnent of theneck 30 with the opposite wall terminals 23 of the body section, so thatthe element I4 is thus confined to substantially a degree swing.

The companion elements or body halves I I -I2 aresecured together and'inassembly with the annulus of the member I4 and the end 8 of the bracketarm 5, by novel fastening means employing attachm'ent elements ofspring-clip character which maybe easily manually applied or removed.The fastening arrangement further issuch as to leave the interior of thebody section III substantially unobstructed, "except for the portions ofthe hearing rings 36 and annulus 28 which extend transverselytherethrough, whereby to provide for the relatively free extension ofthe conductor cable 9 longitudinallythrough the joint in the mannershown in Fig. 2. Referring particularly to Figs. '4, 6, and 9, a pair ofclip elements 40 are formed from suitable spring material, and each hasthe general configuration as-shown by the perspective viewof Fig. 9.Each clip is of generally U- shape or saddledorm, providing a curvedbody portion 4I characterized by a degree of curvature correspondingsubstantially to the surface curvature of the companion elements II andI2, and spring arms 42 each-appreciably reduced in the manner shown. Toaccommodate these securingelem'ent's, 'each of the elements H and I2 hasits'o'pposite wall-portions -22 'recessed'in the external surfacethereof, as at 43, and provided with apertures 44 transverselytherethrough from the base of the recesses. Therec'esses and aperturesin the adjacent corresponding walls 22 of the companionelementsfcooperate when these body parts are brought together (Fig. 4),to receive the clip body 41 such that its curved outer surface issubstantially'flush with the outer surface of the assembled joint bodysection II], and to receive the spring arms 42 through the apertures 44.These "clips'being thus disposed in the diametrically opposedpositionand straddling rel'ation to the elements II and I'Z as appears in Fig.4, serve most efl'ectively to connect these body elements and to holdthem in assembly engagement with the annulus 28 of member I4, as well aswith the end 8'of the bracket-arm 5.

It is 'a further pur ose of -my invention to utilize the sprin clipsMinot only "-for effecting assembly of the joint parts, but astensioning elements for thebody'sectionil whereby-the latter is causedto engage both the bracket ar'mtand the annulus 28 of the joint memberI4 with such pressure as toefiect yieldable frictional retention or thebodysection in any positlonof rotary ad- Also, the zone of applicationof the clips 40 to the] body section III is substantially midway betweenthe ends of the latter, as shown by Figs. 2 and 6. As a result, thespring clips 40 being under tension in application, will tend to drawthe body parts together, and in consequence thereof, these companionelements II and I2 coact at their opposite corresponding ends to eifectthe desired frictional engagement with the bracket arm 5 and annulus 28of joint member l4.

It will be now observed that I have provided an especially compact jointwhich fully attains all of the objects herein expressed, as well asother objects and advantages now readily apparent. By reason of itssubstantially universal adjustability, my improved joint is particularlysuitable for use in articulated brackets for supporting electricaldevices such as lighting fixtures and the like.

Having described my invention in connection with the disclosure herein,or a preferred embodiment thereof, what I regard as new and desire tosecure by Letters Patent is:

1. A joint of the character described comprising an elongated bodydivided longitudinally into sections and having an axial bore at one endto receive an end portion of a bracket member, said 1 the inner sides ofthe bearing arms, a joint member having an annular head portionrotatably positioned between said bearing arms, ring elementsinterposing the adjacent mating surfaces of said head portion, andmeanspreventing rotation of said ring elements with respect to thebearing arms, said ring elements providing facings for the edge surfacesof said head portion such as are exposed to the electrical conductors insaid cavities, whereby to protect said conductors against rubbingcontact with said head portion, and resilient clips interconnectingadjacent external marginal portions of said sections for holding therecited parts in assembly.

2. In a joint for connecting adjacent arms of an adjustable fixturebracket, a hollow elongated body divided longitudinally into pairedsections, said sections being formed to provide an axial bore at one endof the body to receive and be rotatably mounted on the end portion of abracket an opening flanked by arcuate faces on the opposedmargin of saidsections, bearing rings fixedly disposed on said arcuate bearing faces,an annular member having a tubular neck extend ing radially therefrom toreceive the end portion of a second bracket arm, said annular memberbeing rotatably mounted in the body between said bearing rings, andexternally mounted, U-shaped resilient clips embracing adjacent marginalportions of said sections, said clips holding the body sections in'pressure engagement with the first said bracket arm at one end of saidbody and with said annular member at the opposite end of the body,whereby frictionally to restrain relative rotation of these members inthe body.

ALBERT C. PERBAL.

